Harris and Trump Bet on Their Own Sharply Contrasting Views of America

Ms. Harris got under his skin repeatedly, needling him and putting him on the defensive. Indeed, while judges have scolded him and prosecutors have accused him, no one in years has trolled Mr. Trump to his face on a public stage quite like she did. His Republican primary opponents went easy on him, and Mr. Biden was spectacularly ineffective at taking him on during their debate on June 27 before the president dropped out of the race.

By contrast, Ms. Harris, the former prosecutor, calmly and confidently poked at Mr. Trump’s sensitive spots time and again, litigating the political case against a candidate who was convicted of 34 felonies, indicted three other times, found liable of sexual abuse in one civil trial and of business fraud in another and tried to overturn an election that he lost. He scowled much of the evening, refusing even to look at her.

Whether many voters change their minds one way or the other as a result of the back-and-forth remains to be seen. Mr. Trump’s strong support from his Republican base has been locked in for months, largely unaffected by events, favorable or otherwise. He has not been losing many voters nor gaining them, although he remains unable to crack the magic 50 percent threshold.

Ms. Harris, on the other hand, had more to gain or lose on Tuesday night as the new candidate in the race, reintroducing herself to tens of millions of viewers evaluating her as a potential commander in chief for the first time.

A CNN flash poll found that she won by a nearly two-to-one margin and the professional commentariat seemed to agree, including some conservatives. By any measure, she did better than Mr. Biden, whose shaky performance in June was so bad that it forced him from the race. But as Hillary Clinton can attest, debates do not always translate to victory in November.

If there are no more debates, then the two candidates will now separately crisscross their two Americas for the next 55 days in a high-stakes, this-is-for-all-the-marbles test of which one has a better sense of the country. And then it will be left to voters who are angry and voters who are exhausted — and those who are both — to decide which America they see and what kind of America they want to live in.